Conduction type transition of magnetron-sputtered CuO thin films dependent on annealing temperature

• 1、School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028

Abstract：In this study, Li-doped CuO thin films were prepared via magnetron sputtering, and the effects of annealing temperature on the crystal structure, optical properties, and electrical properties of the films were systematically investigated. The films exhibited n-type conductivity at relatively low annealing temperatures (≤ 450 C) and transformed to p-type conductivity at higher annealing temperatures (≥ 500 C). The results indicate that 500 C in air atmosphere is the critical temperature for the elimination of oxygen vacancies in CuO, while 550 C is the temperature at which the Cu vacancy concentration reaches a relatively stable state. Overall, with increasing annealing temperature, the carrier mobility of the films increases gradually, and the optical absorption edge shows a blue shift. The band gap variation is closely related to the evolution of dominant conductive defects in the films. Specifically, the band gap is narrow when oxygen vacancies are dominant, whereas it becomes wider when Cu vacancies and Li-doping defects dominate. This work demonstrates that stable n-type and p-type CuO-based materials can be obtained separately under appropriate conditions, which provides feasibility for the construction of CuO homojunction p-n devices and shows potential application prospects in thin-film solar cells, near-infrared photodetectors, and other fields.In this paper

Keywords： Magnetron sputtering Li-doped CuO Film Electrical Properties Optical Properties